Apparatus for dehydrating liquid coating products and the like



Aug. 29, .1944; P. M. FLEURIEL 2,355,758

APPARATUS FOR DEHYDRATING LIQUID (:OATING PRODUCTS MID THE LIKE Fil ed13:14, 1942 v 3 g ej'fi Patented Aug. 29, 1944 APPARATUS FOR DEHYDRATINGLIQUID COATING PRODUCTS AND THE LIKE Paul M. Fleuriel, Stow, Mass,assignor to Union- Baystate Co. Inc., Cambridge, Mass., a. corporationof Massachusetts Application December 4, 1942, Serial No. 467,851

3 Claims.

This invention relates to the manufacture of liquid coating products,such as liquid finishes for leather and other material, which comprise apigment and other solid ingredients held in suspension in a liquidvehicle, usually a more or less volatile vehicle which will evaporatewhen exposed to the air or whensubjected to the action of a heateddrying medium.

Such liquid coating products are universally packaged and sold inready-to-use liquid form, and in thi form the liquid vehicle constitutesa considerable proportionof the weight and bulk or volume of any givenquantity of the product.

One of the objects of my invention is to provide a novel apparatus fortreating such liquid coating products so as to remove the liquidvehicle, and in so doing, leaving the solid ingredients in the form of apowder, each particle of which contains all the solid ingredients of theliquid coating product and in the same proportions as they exist in theready-to-use form of the product.

Such powder can be packaged and shipped for a fraction of the cost ofpackaging and shipping the equivalent amount of ready-to-use liquidcoating, vand can be readily converted into a liquid coating ready foruse by simply stirring a given quantity of the powder material into thecorrect quantity of liquid vehicle. Since each particle of the powdercontains all the ingredients of the ready-to-use liquid product exceptthe liquid vehicle, and in the same proportion as they exist in theready-to-use product, the

mere operation of stirring the powder into the drating apparatusembodying my invention.

Fig. 2 is a plan view with a part broken out.

Fig. 3 is a section on the line 3-3, Fig. 1.

In the drawing I and 2 indicate two dehydrating chambers both of whichare preferably cylindrical in shape. The dehydrating chamber Iconstitutes what I will refer to as a primary dehydrating chamber, whilethe chamber 2 constitutes what will be referred to as a secondarydehydrating chamber. These two chambers are connected at their lowerends by means of a pipe or conduit 3 which leads into each chamber in atangential direction as best seen in Fig. 3.

The primary chamber I is closed at its top as shown at 4 and is providedwith a spray nozzle 5 which communicates with a suitable supply pipe 6.Said spray nozzle may be of any desired construction ,but willpreferably be a nozzle which will deliver liquid from the pipe 6 intothe chamber I in the form of a fine spray composed of minute droplets.

The secondary dehydrating chamber 2 has its upper end closed by means ofa diaphragm I in the form of a dust filter. This diaphragm I may be madeof any suitable material which will permit the passage therethrough ofgaseous medium but will prevent the passage therethrough of any solidmatter even in the form of a fine dust. The diaphragm 'I-may be securedto the chamber 2 in any appropriate way as by means of the clamping band8 which encircles the chamber 2 and by'means of which the peripheralportion of the filter member I is clamped to the outside of the chamber2.

Means are provided for delivering a gaseous drying medium under pressureinto the upper end of the primary dehydrating chamber I, such dryingmedium being so delivered into the chamber that it will have a whirlingmovement in the chamber as it moves downwardly through said chamber tothe outlet opening 9'leading to the conduit 3. For this purpose there isprovided an inlet pipe III which leads into the upper end of the primarydehydrating chamber I in a tangential direction and through which theheated drying medium is delivered to said chamber. This drying mediummay be heated and placed under pressure by any approved means. For thispurpose, I have indicated a fan or blower II which is mounted in ahousing I2 and which delivers the drying medium under pressure to thepipe I0. I3 indicates a suitable heater element over or through whichthe drying/medium is forced by the fan or blower II thereby heating thedrying medium tothe desired temperature.

The heated drying medium which is delivered into the primary dehydratingchamber I through the pipe Ill will have a whirling motion in saidchamber as indicated by the scroll line I4, the arrows applied to saidline indicating the direction of the whirlingv movement of the heatingmedium.

As stated, the spray or atomizing nozzle 5 delivers the liquid to betreated into the upper end of the dehydrating chamber I in the form of aflows downward in the primary chamber I dur- I ing its whirling movementand is discharged through the discharge port 9 and conduit 3 into thelower end of the larger secondary dehydrating chamber2.

Since the conduit 3 delivers into the secondary I dehydrating chamber 2in a tangential direction, the drying medium issuing from the conduit 3will have a whirling motion in said secondary chamber -2 as indicated bythe scroll line I5, and this drying medium will have a gradual upwardprogress through the chamber 2 and will finally filter through thefilter member I at the top of the chamber as shown by the arrows.

Assuming that the liquid which is being sprayed from the nozzle 5 is aliquid coating product comprising pigment and other solid ingredi entsheld in suspension in a liquid vehicle, each minute droplet which isdelivered from the spray nozzle 5 will contain all the ingredients ofthe liquid coating material in the same proportion as they exist in theproduct before it is broken up into minute droplets by the spray, thatis, each droplet will contain all the solid ingredients of the liquidcoating held in suspension in a droplet of the liquid vehicle and in thesame proportion that they exist in the larger quantity of liquidcoating.

As each of these minute droplets is circulate through the primary dryingchamber by the whirling current of drying medium, the liquid vehicle ofeach droplet is gradually evaporated, and when the liquid vehicle ofeach droplethas been completely evaporated, the residue will be a minuteor small particle of solid matter which contains all the solidingredients of the readyto-use liquid coating and in the same proportionas these ingredients exist in such ready-to-use coating.

The solid residue of any droplet which is completely dehydrated in theprimary drying chamber I may gravitate to the bottom I6 of said chamberor may remain entrained in the gaseous drying medium along with dropletsthat are not entirely dehydrated and thus be carried over into thebottom of the dehydrating chamber 2 through the conduit 3. The bottom I6of the chamber I is in the form of a dust collector and is provided withan opening II normally closed by a closure I3 and through which theaccumulated dust particles can be removed. 7

Because of the tangential arrangement of the conduit 3 with relation tothe chamber 2, the stream of gaseous drying medium entering the chamber2 through said conduit will have a whirling motion in the chamber, andbecause the upper end of said chamber 2 is closed with a filteringdiaphragm l, the whirling current of drying medium in said chamber 2will have a gradu-- ally rising movement. The dehydrating action of theminute droplets continues and is completed in the chamber 2.

Inasmuch as said secondary dehydrating chamber 2 is of somewhat largerdiameter than the dehydrating chamber I, the whirling current of gaseousmedium in the secondary chamber 2 will have a reduced speed as comparedwith the speed of the whirling motion in the primary dehydratingchamber, and this reduction of speed is such that each solid particleconstituting the residue of a dehydrated droplet will gradually settleto the bottom I 9 of said dehydrating chamber 2.

Said chamber 2 is provided with a discharge ening 20 in its bottomnormally closed by a removable closure'2l and through which thedehydrated particles accumulating in the bottom I9 of the chamber may beremoved.

Because of the reduced velocityof the current of drying medium in thesecondary dehydrating chamber 2, the dust particles have an opportunityto become cooled somewhat while they are settling out or the whirlingcurrent and thus the chamber 2 constitutes not only a secondarydehydrating chamber but also a cooling chamber.

22 indicates a damper or valve in the conduit 3 by which the flow of thegaseous medium therethrough can be regulated. By partially closing thisdamper or valve so as to cut down the free flow of gaseous mediumtherethrough, the individual droplets delivered from the spray 5 will beretained in the primary dehydrating chamber for a longer period of timethan when the valve 22 is fully opened.

The provision of thiscvalve or damper 22 makes it possible to use'theapparatus for drying or dehydrating materials having difierent specificgravities. When dehydrating material with a high specific gravity, thevalve 22 will be partially closed thus restricting the flow of gaseousmedium through the conduit 3. In this way, the higher specific gravityof the material will be offset by the back pressure thus built up in thedehydrating chamber I, and the individual droplets will be preventedfrom settling too rapidly in said chamber I or from being carried intothe secondary chamber 2 prematurely. I

In this way it is possible to so regulate the movement of the dropletsand particles downwardly through the primary chamber I and upwardlythrough the secondary chamber 2 that all droplets or particles will becompletely dried before they settle out of the upwardly moving aircurrent in chamber 2.

For drying material having a relatively light specific gravity,the-valve 22 may be fully opened or so positioned as to only slightlyrestrict the movement of the drying medium through the conduit 3. Theminute particles of the material having a light specific gravity do nottend to move downwardly in the chamber I as rapidly as the particleshaving a heavier specific gravity, and therefore, when drying materialof a relatively light specific gravity, the damper 22 may be adjusted topermit a freer flow of the gaseous medium.

Since each particle of the powder material which accumulates in thelower end of the dehydrating chambers contains "all the solidingredients of the ready-to-use liquid coating and in the sameproportion in which these ingredients are found in said liquid coating,a liquid coating product similar to that which was fed to the spraynozzle 5 can be produced by simply stirring a given quantity of powderwith the correct amount of liquid finish and without the necessity ofsubjecting the product to any grinding or similar operation to secure ahomogeneous mixture.

I claim: v

l. A dehydrating apparatus comprising'a primary cylindrical dehydratingchamber, means to deliver heated gaseous drying medium under pressureinto the upper end of said chamber in a tangential direction, means todeliver the liquid to be dehydrated into the upper end of said chamberin the form of alspray, a secondary cylindrical dehydrating chamber oflarger diameter than that of the primary dehydrating chamber, and aconduit connecting the lower end of the primary dehydrating chamber tothe lower end or the secondary dehydrating chamber and having atangential relation to both chambers. said secondary dehydrating chamberhaving its I upper end closed by a filtering diaphragm, whereby saiddrying medium with its entrained droplets of the liquid fiows downwardlythrough the primary dehydrating chamber with a rapid whirling movementand flows upwardly through the secondary dehydrating chamber with awhirling movement of decreased velocity.

2. A dehydrating apparatus comprising a primary cylindrical dehydratingchamber, means to deliver heated gaseous drying medium under pressureinto the upper end of said chamber in a tangential direction, means todeliver the liquid to be dehydrated into the upper end of said deliverheated gaseous drying medium under pressure into the upper end of saidchamber in a tangential direction, means to deliver the liquid to bedehydrated into the upper end of said chamber in the form of a spray, asecondary cylindrical dehydrating chamber 01' larger diameter than thatof the primary dehydrating cham-.

her, a conduit connecting the lower end or the primary dehydratingchamber to the lower end of the secondary dehydrating chamber and havinsa tangential relation to the latter, and means for controlling the flowof heated gaseous drying medium through said conduit.

PAUL M. FLEURIEL.

